Magnetic recording system for call data in automatic telephony



April 29, 1952 JQ B. RETALLACK A MAGNETIC RECORDING SYSTEM FOR CALL DATA IN AUTOMATIC TELEPHONY Filed Sept. 4, 1947 8 Sheets-Sheet l IIII NGN `QN QON Y IIB IID /N VEN TOR J 5. REMLLACK ATTORNEY April 29, 1952 J. B. RETALLACK MAGNETIC RECORDING SYSTEM FOR CALL DATA IN AUTOMATIC TELEPHONY Filed sept. 4, 1947 8 Sheets-Sheet 2 N .um

BN QON /NVEA/ron J B. RETALLACK April 29, 1952 J. B. RETALLACK MAGNETIC RECORDING SYSTEM FOR CALL DATA IN AUTOMATIC `TELEPHONY Filed Sept. 4, 1947 MOM /NVENTOR J. B. RE'ALLACK A TTORNFV April 29, 1952 -.1. B. RETALLACK MAGNETIC RECORDING SYSTEM FOR CALL DATA IN AUTOMATIC TELEPHONY Filed Sept. 4, 1947 8 Sheets-Sheet 4 MAGNETIC RECORDING SYSTEM FOR CALL DATA IN AUTOMATIC TELEPHONY vFiled sept. 4, 1947 v 8 Sheets-Sheet 5 W11 d m m L.) m

/NI/ENTOR -J. BJPELLACK BY n A T'ORNEY April 29, 1952 J. B. RETALLACK MAGNETIC RECORDING SYSTEM FOR CALL DATA IN AUTOMATIC TELEPHONY Filed Sept. 4, 1947 /NVENTOR J 5. RETLLCK ATTQRNEY April 29, 1952 J. B. RETALLACK 2,594,495

MAGNETIC RECORDING SYSTEM FOR CALL DATA IN AUTOMATIC TELEPHONY Filed sept. 4, 1947 s sheets-sheet 7 V To LAST sENoE/e lllllllll T0 LAST TRI/Nl( T0 INTERMEDIATE SENDER lllllllill llllllll V; /N VE N TOR J. B. REALLACK ATTORNEY J. B. RETALLACK April 29, 1952- MAGNETIORECORDING sYsTEM `FOR CALL DATA 1N AUTOMATIC TELEPHONY Filed sept. 4, 1947 a sheets-sheet s mmm mm m'mm /Nl/E/VTOR J. @.RErALLAc/f E 6, M

ATTORNEY Patented Apr. 29, 1952 MAGNETIC RECORDING SYSTEM FOR CALL DATA IN AUTOMATIC TELEPHONY John B. Retallack, New York, N. Y., assignor to Bell Telephone Laboratories, Incorporated, New York, N. VY., a corporation of New York Application September 4, 19,47, Serial No. 772,091

1o claims. (c1. 17g-m1) "This invention relates to a telephone systemfor enabling calling subscribers to control the establishment of toll connections by dialing and in which system signals of different frequency combinations are recorded on a magnetic recorder in accordance with the data required for billing a toll call and in which system the information recorded on the magnetic recorder may be transmitted to a receiving circuit arranged to produce a card or other record containing the billing data for usein an accounting machine. The invention relates more particularly to improvements in a system oi. the general type disclosed in my PatentNo. 2,447,533, granted August 24, 1948.

In the system of my patent referenced above, a group of automatic ticketing trunks is provided, each trunk having a ticket printer. A subscriber desiring a connection to a line terminating in an oice in the nearby toll area dials the oiiice code and numerical digits Aof the wanted line number and in response to the dialing of one or more of the oilce code digits a connection is extended to an idle one of the ticketing trunks which have access to the office in which the Wanted'line terminates. Immediately following the seizure of an idle trunk, an idle sender'common to the vticketing trunks is associated with the seized trunk. The sender is provided with registers for registering the digits of a called line number dialed by the calling subscriber and with registers for registering the digits of the calling line number, which number can be supplied to said sender by an associable identier.

As soon as the first digit has been registered in the sender, which digit may be either the third office digit, the thousands digit or .the hundreds digit, an idle identier is lassociated with the sender over an identifier connector and the identifier is associated directly with the trunk over an identifier trunk connector.` Thereupon, thel identifier reconstructs the oflice code dialed by the calling subscriber, which information may be derived Afrom the trunk or from the trunk and sender and transmits this information to the sender. The identier also proceeds to identify the calling line and to transmit information concerning the designa-tion digits of such calling line to the sender.

The sender'after registering the digits of the wanted line number transmitted to it from the identifier and the digits of the wanted number dialed into the sender from the calling line, proceeds to direct the setting of selector switches to extend a connection from the ticketing trunk to the wanted subscribers line. Such called ofilce code and numerical registrations are also effective to control the printer of the trunk to print on the toll ticket, the office code and numerical digits which identify the called line. In addition, the resignations of the oiiice code and numerical digits of the calling line transferred to the sender from the identier are effective to control the printer to print such digits on the toll ticket. Provision is also made for printing other data required for ticketing the call such as the date and time the call was made and the elapsed time of the` conversation.

One object of the presen'tfinvention is to further improve an automatic ticketing system of the type above described and particularly toimprove the ticketing trunk whereby a magnetic recording unit is controlled by the sender and the trunk to record thereon the previously mentioned billing data.

Another object of the present inventionvis to record such data on such a magnetic recorder by means of utilizing combinations of alternating current frequencies to represent digits of such data and impressing such frequencies upon a magnetic tape in said recorder.

It is a further object of the invention to provide receiving circuits at a central accounting oiiice controlled by said trunk for seasonably enabling said recorder to transmit the recorded data to said circuits to be there converted from combinations of alternating frequencies to digits of data for the purpose of producing a card or other record containing such data and usable in wellknown types of accounting machines. Other advantages and objects of the invention will be apparent to those skilled in the art from the subsequent detailed description of one embodiment of the invention. This description is augmented by the drawings forming a part of the disclosure, of which drawings the following are general descriptions of the various figures comprising same.

Fig. 1 shows a calling subscribers line, the schematic representation of a line nderjand rst, second and third selector switches over` which access may be had to an idle one of a plurality of automatic ticketing trunks, one of which is partly disclosed in Figs. 2, 3 and 4; V

Figs. 2, 3 and 4 taken together show suii'icient parts of a ticketing trunk for the purpose of explaining the invention and including a duration of conversation register and a magnetic recorder;

Fig. 4 discloses schematically ,certain parts 'of one of a plurality of link circuits connectable between the trunk and a register with associated accounting apparatus in a central accounting oice;

Fig. 5 shows schematically parts of an identiiier circuit associable with the subscribers line of Fig. 1, with the trunk of Figs. 2, 3 and 4 and with a sender, partly disclosed in Fig. 6;

Fig. 6 shows sufficient parts of a sender to enable an understanding of the present invention;

Fig. 7 shows a sender-trunk connector for connecting any seized sender with the ticketing trunk which has seized said sender;

Fig. 8 shows a group of alternating current generators of the vacuum tube type associated with said trunk and usable by a sender seized by said trunk; and

Fig. 9 shows an arrangement of Figures 1 through 8 such that the assembled group of flgures as a whole discloses an automatic ticketing system embodying the present invention.

The line finder |0| and the selector switches |02, |03 and |04 of Fig. 1 are of the well-known step-by-step type and the selector switches are operative in response to the dial of a calling line to establish local connections or to establish a connection with an idle automatic ticketing trunk, such as is disclosed partly in Figs. 2, 3 and 4, should the subscriber desire a connection to a subscribers line which terminates in the toll area adjacent to the exchange area in which the calling line terminates. ticketing trunk of Figs. 2, 3 and 4 has a branch which terminates in the bank of a first selector |02, another branch which terminates in the bank of a second selector |03, and still another branch which terminates in a bank of a third selector |04 whereby the trunk may be seizedin response to the dialing of the rst oiice code digit of a certain distant oflice, in response to the dialing of the rst and secondV office code digits of another oifice and in response to the dialing of the three ofce code digits of still another ofce.

The elapsed time registers 300 and 350`and the elapsed time progress switch 250 associated with the ticketing trunk and the progress switch 650 of the sender are of the well-known rotary step-by-step type. The brush of the progress switch 250 is advanced step by step in response to the operation of the stepping magnet 253 and is restored by the operation of release magnet 254. The brushes and302 of register 300 areadvancedstep by step by stepping magnet 303 and are restored by release magnet 304 and the brushes of register 350 and progress switch 650 are advanced step by step from their normal positions and are returned to their normal positions by a further forward stepping movement.

Thev ticket recording mechanism360 associated with the automatic ticketing trunk comprises a magnetic tape 313 operable by drums 321 and 328 and kept taut by means of spring 329. a gear train 3|2 for rotating said drums when said gear train is operated by a motor 3|| and a combination magnetizing, pick-up and Wipefout coil 314.

Two trunk finders of the step-by-step double brush set type are individualized to each sender. One of such trunk finders is schematically disclosed in Fig 5. Each of the trunk nders has access to the terminals in which control conductors from one hundred ticketing trunks terinmate.

y Since a trunk nder does not have sufiicient brushesv in both of its brush setsto accommodate all of the controlconductors required between a As disclosed, the

trunk and a sender, a plurality of additional sender-trunk connector circuits is provided, that shown in Fig. 7 having a multicontact relay individual to each sender and ten multicontact relays individual respectively to ten trunks. Ten of such circuits serve the above said group of one hundred trunks to Which the trunk finder of Fig. 5 has access.

Only so much of one of the senders is disclosed as is deemed necessary for a complete understanding of the invention, only two `of the registers of the sender being partly disclosed in Fig. 6 and the circuits, among others, for controlling cut-pulsing being omitted. The month, day and hour circuit and identifier have been disclosed only diagrammatically as they are concerned only incidentally with the present invention. For a full disclosure of the entire system to which the present invention is applicable, reference may be had to my Patent No. 2,447,533 hereinbefore referred to, and to the copending application of J. W. Gooderham, Serial No. 448,782, led June 27, 1942.

To more clearly set forth the novel features of the invention, it will first be assumed that the party whose substation is identified by the numeral |00 in Fig. 1, initiates a call for a toll connection to a subscribers line terminating in an office of a toll area to which the calling subscriber is permitted access by dialing. Upon the removal of the receiver from the switchhook. an idle line finder havingaccess to the calling line, such as the line nder |0|, is started in search of the calling line in a well-known manner. When the line finder has found the calling' line the usual dial tone is transmitted over the calling line to inform the subscriber that his line has been connected with a-rst selector |02, paired with the line finder |0|, and that he may therefore commence dialing the digits of the wanted line number.

It will be assumed that the calling subscriber desires a connection with a line whose directory number is MAR-1345 and a ticketing trunk over which the connection may be extended may be reached from the sixth level of the bank of first selector |02. The calling subscriber upon hearing the dia-l tone therefore proceeds to dial the office code letters M, A, R and the numerical digits 1, 3, 4 and 5. Inresponse tothe dialingv of the rst ofIice code letter M, which has anumerical equivalent 6, the rstselector |02 is operated to elevate its brush set toa position opposite the sixth bank level and to then hunt over the terminals of this level in search'of an idle ticketing trunk. It will be assumed that the trunk disclosed in Figs. 2, 3 and 4 is idle and that therefore when the test or sleeve brush of selector |02 engages the test or sleeve terminal |05 of the branch of this trunk, it finds no busy ground potential thereon and therefore the selector seizes the trunk. A circuit is thereupon effective from ground at the selector over the sleeve conductor 202 of the trunk, through the upper normal contacts and upper windingof sleeve relay 203, through the winding of relay 204 and in parallel therewith over the back contact of relay 204 and through' resistance 205 to battery and ground. Relay 203 operates from the low resistance battery thus supplied, locks from battery through its lower winding and over its lower front contact to the sleeve conductor 202, opens the initial operating circuit through its upper winding, connects its lower winding over its upper and lower front contacts in paralgie-154135 lel with the winding of relay 201|, and prepares a'circuit over its inner lower front contact for a purpose to be later described. Relay 204 also operates and removes resistance 205 fromthe parallel connection with its winding. As soon as the talking circuit is out through at the selector |02, (not shown) is established for slowto-release relay 206 and ground is connected to the trunk start conductor which is common to the ten trunks of' a subgroup and establishes a connection from ground and battery through the winding of relay 201 to a conductor which marks the trunk as calling so that the started trunk finder will stop on the terminals of such trunk. Relay 206, upon operating, connects ground over the lower No. 2 back contact of relay 208, the lower front contact of relay 206, conductor 209, over the inner No. normal contacts cf relay 2|0, the upper contacts and through the lower winding ofsleeve relay 203 to battery for holding the sleeve relay operated after ground is removed at the selector |02, and over the lower contacts of relay 203 to sleeve conductor 202 of the trunk to hold the selector |02 and the line finder from releasing. Relay 206 will remain operated during the opening of the loop circuit caused by open line impulses-of dialed digits or characters.

When the trunk nder seizes the terminals of the calling trunk and completes the previously mentioned circuit for relay 201, relay 201 operates and locks to a ground supplied from the trunk finder and at a later time from the selected sender. Relay 201 holds relay 206 operated over the circuit extending over the outer contacts of relay 201 and to ground at the lower No. 4 contact of relay 2 I 6. If there is no idle sender available relay 201 will not operate and relay 206 will therefore release and in doing so will effect the release of sleeve relay 203, relay 204, line finder |0| and first selector |02. If, as we assume, an idle sender is found then relay 201 operates as above and the dialing circuit of the line loop is transferred to the selected sender which will receive the second oiiice code designation. l

When the iirst digit (the third oiilce code designation dialed by the calling subscriber) has been received in the sender an idle identifier is associated with the sender by means of a senderidentier connector (Fig. 5) and the identifier is associated with the calling ticketing trunk by an -identifier trunk connector circuit (Fig. A5). The operations of the identifier circuits need not be described in detail herein for an understanding of the features of the present invention. Identier circuits and the functions thereof which are pertinent to the operation of a system capable of embodying the present invention are fully disclosed in the copending application of J. W. Gooderham Serial No. 448,782, filed June 27, 1942. General reference only is made to the identifier shown schematically in Fig. 5 in connection with its cooperation with the trunk, the sender and the calling line. Upon the operation of the identifier trunk connector a circuit is established for the three-positionpolarized relay 2|0 of the trunk, relay 2|0 thereby operating its upper contacts to complete extension of control conductors from the trunk to the sender. p

A circuit is at this point established which may be traced in part from battery applied at the identifier over contacts of the identifier trunk gonnectonthence over conductor 2|2, the upper No. 4 contacts. of relay 2|0, over the inner-lower. contacts of sleeve relay 203, code lead 2|3 and contact of the identifier trunk connector .to the identifier for registering in the identifier the first code digit dialed to set the selecteer |02 and a further circuit is established to transfer the second code digit assumed to be registered in the trunk to the identifier. If the first digit registered in the sender was the `third code digit,

inbefore referred to. Relay 2|0 at its upper No. Y

back contact opens 'the shunt around retard coil 2M and at its upper No. alternate contacts extends a connection from sleeve conductor 202 of the trunk, over the lower contacts of sleeve relay 203, Athe upper contacts of relay' 203, the upper No. alternate contacts of relay 2|0, over conductor 2|5 and thence over contacts ofthe identifier trunk connector to the identifier over which circuit the identifier applies 270-cycle identifying tone current .towards the calling line.

Following the association ofthe identifier with the trunk, the identifier is started to identify the calling line. As soon as the identification of the calling line is completed and the necessary information concerning the identity of the calling ofnce, the numerical digits of the directory number of the calling line and the class of the. call.- ing line, have been registered in the identifier, this information is transferred to the sender and results in tli'e setting of register relays therein'. One register is set in accordance with the `calling oiiice unit in which the calling line is located from the setting of which the three ofiice code digits of the calling line number may be secured and four other registers are set to register the thousands, hundreds, tens and units numerical digits of the calling line number (seeFig. (i).

When all of the digits of the called line number have been transferred to the called oflice code and numerical registers of the sender a checlrtest is made to determine if the proper number of relays of each register have been operated. When all of the calling line number and class information has been transferred to the sender another check test is made to determinefif the proper number of register relays have been operated and if so relay 600 operates and locks in a circuit from battery through its winding over its lower frontV contacts to ground on an ofi-normal conductor 00|. v .l

Following the registration of the called office code digits in the sender, the sender proceeds to control the completion of the connection .of the wanted line in accordance with the office :code and numerical digits of the wanted line number. When the last digit of such called line num-ber has been dialed into the sender and when thelast series of impulses has been sent from'the sender to set a connector upon the lterminals of the wanted line, sufficient current is permittedfto fiow through the windings of relay 2|0 ofthe trunk to cause the latter relay to operate inthe positive direction to operate its lower contacts. Relay 2 I0 thereupon establishes acircuit over its lower No.y 2 lfront contact forcut-through. relay 4216 which operates andlocks over ,its 'lower outer The.

.eminent frontcontact to ground over: the upper front contact o'frelayx206.

.it the ltrunk, `relayf2 I 6 opens lthe dialing loop extending from .the calling line tozthesender and atlits upper No. Isand lowerNo. i2 front contacts connectsthe calling line,.extended .totipand ring conductors 200|.and '20 I ,sto the windings .of supervisory relay 2I-'I. Relay V2'I'I :now .operates ina circuit whichrmay be .traced Vfrom/.the .tip trunk conductor S200 over Athe upper No. I contacts of relay 216, conductor 2 I8,.through the upper left winding .of Lrepeating coil '2 I 9 Vand n.the upper. No. 4 fhack aconta'ct Vof :relay v22I :to ground ,through .theaupper-.winding of .relayl 2.I 'I .and `from Y,the ring .conductor.220l, .over the lower No. 2i'frontcontact of relay12 I3, conductor22 I'.throug`h the lower left 'winding 'ofirepeating .coil 2 I 9 ,and overptheiupper No. :Siback contact of relay'22'0 to' battery through the lower-winding of relay 2 If'I. Relay 2|.'I operates andcloses a' circuitifor 'holding relay 266 operatedwhichmaybe traced from battery through the winding of relay 20S, over lthe contacts Aof relay-2 I 'I to 1groundaoverthe inner lowerv contacts of "relay 206. With'rel'ay 2I6 operated `the original;locking vcircuit forrelay 206 .is opened Vand r.elay-,26 isnow held operatedentirely under the control of Vthe .calling subscriber to V,control .the lholding of .thetrunlc .Relay 2I6 also establishes a 'circuitv extending to the :called .line which ymay he traced '.inpartffrom the Atip .conductor vof the calledline;over;conductor 222, over contacts (not shown) ,of `relay ;2I6, through the upper Aright winding of Vrepeating coil 2I9, the winding of polarized :supervisory .relay 223, conductor 22.4, the lower :right winding of repeating coil 2I9, over contacts '.(notzshown) of relay v2 I6, and conductor 225 to thering conductor of the called line. l.Relay-223 being'polarized does ynot receive current in the'rightdirection at this'time to cause its operation.

Response .of ,the calledsubscriber Whentthe called subscriber answers, the direction'of currentflowing through the winding of supervisory relay 223 is reversed whereupon relay f its lower No. 2 contacts and the circuit previously f tracedto the sleeve conductor 262 of the trunk to replace the ground supplied to such circuit over 4the lower No.2 vback contact of relay y2il8 lafter relay A288 operates-as will be presently described. Assoonrfollowing lthe operation of relay 1226as ground is `applied over conductor 221 at themiscellaneous interrupter frame. a circuit is completed over the lower No. 12'normal'contacts of relay 228, over conductor 229, thelower No. I contacts yof relay 2I6, conductor 239, the lower No. -3 contactsof relay 226 and-over the upper No. 3 back contact of relay 208=to battery through Athelower winding of relayf228. Relay 228 thereyupon'operates v:locking-to direct ground over its lower'No. f2 alternate contacts and connecting ground lover itsupper No.4 contacts and over the upper'Noi3'bacli contact of lrelay'253 to'start vv`conductor-23l -extending tothe miscellaneous interrupter iframe to :start the measurement of Va time-interval. After two 'seconds delay, ground nwill `be zapplied 'to conductor 232 at the interlrupter frame thereby completing a circuit over itheupper No..f3:contactsvof Arelay 228, through the normal :contacts and winding of vrelay .256 lto Mttery, 'whereupon :relay 256 `:operates 1 and `lo cks 8 over itsalternatepontacts over .the upper No.2 back :contact :of relay 220 ,and conductor 23,3 :to ground over .the .upper `normal contacts of -relay 2H.

Timing the conversation yWith-relay 256 operated acircuit is established from ground over a contact of -relay 234, which is operatedonce every fteen seconds bythe telechron clock-operated timer 235, over conductor 236, conductor 237, the lower No. 4 contacts of relay 256, lower No. 2 back contact-of vrelay'ZZIl and over the upper No. `I -contacts fand through the upper winding of relay 228 to hold such relay operatedfandover'the upper No. 2 contacts `of relay 228, conductor 238 Ito battery through the winding of stepping magnet 305 of the units timing register i350. Thus at fifteen-second intervals the brushes-of such 'timing register are 'advanced step-by-step. If the conversationcontinuesuntil the register 350 advances its brushes 352, 354 and 356 to the No. 33 terminals of their -associated arcs, a circuit lwill be closed from'ground applied to conductor 238, thence as traced through the winding of the stepping magnet 365 of register '350 and also over the upper No. '2back contact of relay 239, over brush 356 and the No. 38 terminal of its arc, over the lower No. 3 vback contactof relay 239 to battery through the winding of stepping magnet 333 of the tens timing register 300. The operation Vof magnet 3D3 Awill advance register 396 one terminal thereby caus` ing register 36!) to Iadvance -one step for each revolution of register 35D. In this manner register 350 is'used as a'vmeasure of the'units of conversation time while register 300 measures the tens. The terminals 38 and 39 on the arcs of the units register 353 -are passed by when the tens register 33D has lmade one step or more. The units register 355 alwayspasses by its No. 22 position terminal by the establishment 'of a circuit from ground on brush 35i, over the 'No. 22 position terminal of its -arc and over the inter-v rupter contacts and through the vwinding of stepping magnet 3&5 to battery. The advance of registers 305 and 350 continues in this manner throughout the conversation.

Operation of sender trunk connector After the identifier had transmitted allof .the information to thesender required for thecompletion of -the.connection,.relay '660 .was operated as previously described as a signal .to .thesender to complete the establishment of the connection and thata record should be made. Relay .600 upon operating, locked over itslower front contacts to ground on conductor SGI, caused .the release of the identifier and `established a ,circuit for relay 602 extending v.from battery over the upper contacts .of relay 600, through the winding of relay 602, over the normal `position terminal of the arc ,of switch E) with .which brush 654 should be engaged if the switch isin its normal position, over the normal contacts oistepping re lay 63 to ground on off-.normal ground con-.- ductor 64. Relay 16D21uponoperating locks over its lower No. I contacts ,to ground -on conductor 634 and establishes'a circuit which may be traced from Vbattery through the winding of relay 605, the upper No. I contacts of relay 602 izo-ground applied to conductor 696 from the sender.

Relay 605 upon operating establishes a'circuit which maybe traced frombattery over conductor 661, brush `5IN of -trunk finder 53D, conductorf502,

lthelupper outer-contacts offrelay 605,-,conductor '1508, of cable 609, allocated to the group of ten ticketing trunks appearingin the tenth vertical group of the banks of trunk finder -500 and in which group the calling trunk is located, through the winding of lock-out relay '100 of the sender trunk, connector circuit of Fig. 7, allocated to the first sender assumed tobe in use for the connection and to the vertical group of trunks in which the calling trunk is located, thence to ground over the inner upper normal contacts of lock-out relays of all other senders having access to the same group of trunks of the sender trunk connector circuit if not being used by another sender. Relay 100 operates, locks over its upper alternate contacts to ground, establishes an operating circuit for the multicontact connector relay '101, from ground through the winding of such relay, over the inner lower-front contact of relayv100, through resistance 102 to battery, and establishes a circuit from battery through resistance 103 over the middle upper front contact of relay 100, conductor 104, brush 503 of trunk nder 500, conductor 105, through the winding of multicontact relay 10b` and over conductor 101 to ground over the lower back contact of relay 240. With multicontact relays 10| and 106 now both operated, a plurality of circuit paths is established from the ticketing trunk to the sender for the purpose of transferring registered informationfrom the sender to the recorder 360 of the trunk. Also ground on conductor 111 from the sender trunk connector relay 106 operates relay 301 in Fig. 3 to be explained later in connection with the operation of the recorder 300.

It is to be noted that ten subgroups of ten trunks each of a group of one hundred trunks appear inthe vertical rows of terminal sets of the banks of the trunk finders of the group and that jeachV of the sender trunk connector circuits, of which one is disclosed in Fig. fl, serves a group of ten trunks, such connector circuit having a relay such as 101 for each sender and ten relays, such as 106 for the ten trunks of the subgroup which it serves. Nine similar sender trunk connectors would be provided to serve the other rn'ne subgroups of trunks.

With relays 100 and 10| both operated, a circuit is established from ground over the No. 1 contacts ofsuch relays and conductor 10B to the sender which, as a result of this ground condition, effects the operation of relay 029 to complete `the circuit at its contacts, from ground over contacts of the now operated off-normal relay 310 through brush S52 of switch 650 and the normal terminal of its associated arc, through the winding and interrupter contacts of stepping magnet 611 to battery.V Magnet 611 thereupon operates and releases to-advance the brushes of switch 050 one step whereupon the circuit of magnet $1 1 is opened at brush 052.

Initiation of recording As soon as the sender is connected to the trunk by'means of the sender trunk connector circuits of Fig. 7, and the circuit is established for relay 301 as previously traced, relay 301 operates and connects a source 310 of alternating current to the motor 31 1 of the recorder 330 over the upper and lower front -contacts of relay 301. The motor 31 I will drive the magnetic tape 313, by means of a gear train 312, past the combination magnetising and pick-up coils 3111. as long as the sender trunk connector of Fig. '1 is operated, which will last until the information registered by the sender has been recorded on tape 313.

The coils 314 are at this time connected over the upper and lower inner back contacts of relay 308, upper back contacts or relay 309, upper back contacts of relay 300, over conductors 109 and 110. through the connector relays 106 and 101, over leads 112 and 113, to the front contacts of the multifrequenoy recording relaysat the lower portion of Fig. 6. By means of these relays the information registered on register relays of the sender, such as called line number, calling line number, class of service of the calling line, theV number of the sender and identifier employed, etc., may be transferred, as will be explained, to the magnetic tape 313. This information is recordedon tape 313 in the form of combinations of simultaneously superimposed audible frequencies derived from the oscillators of Fig. 8. A digit or numeral is represented on tape 313 by a combination of two superimposed frequencies.

The circuit of Fig. 8 is fully disclosed and explained in Patent 2,288,251 to P. B. Murphy of June 30, 1942.y It will suice here to say that, as marked on Fig. 8, oscillator 001 generates a 1700.- cycle signal, oscillator 802. a l500cycle signal, etc. The transformers 800 combine thesefrequencies in pairs which represent a start signal, digits and a stop signal. For instance the start signal is composed of frequencies of 1700 cycles and 1300 cycles combined in transformer (ST) and the 'digit 3, for instance, is composed of frequencies of 1500 and 1300 cycles, these frequencies being combined by transformer (3).

With the brushes 052 and 554 of switch 650 on the No. 2 terminals of their arcs and the magnetic tape recorder control conductors 109 to 111 extended over-contacts of relays 106 and 101 of the sender trunk connector circuit, and conductors 112 and 113, respectively. of the sender, a circuit is established from ground on the `off-normal ground conductor 604, over the normal contacts of relay 603, brush 654 and the No. 2 terminal of its arc, conductor 01,2 through the winding of the ST relay to Ybattery and ground. The ST relay operates and connects the secondary of the ST transformer of Fig. 8 through the lower-contacts of the ST relay, conductors 112 and 113, through the sender trunk connector switches of Fig. 7, over leads 103 and 110 to the magnetizing coils 314 of the recorder 300 over the upper back contacts of relays 300 and 300 and the upper and lower inner back contacts of relay 300. Thus a start signal composed of a combination ofL 1700 cycles and 1300 cycles is recorded in the tape 313. When the ST relay operated, an obvious circuit was completed for the interrupter relay 613 over the upper contacts of the ST relay. The armature of relay 613 permits offnormal contacts actu-ated thereby to. connect ground to conductors 614 and 615. With ground connected to conductor 015, the circuit of relay 603 is completed and relay 003 operates, locking overA its lower contacts to ground connected to conductor 014; establishing a circuit for stepping magnet 01 1 which may be traced from ground on conductor 004, over the upper alternate' contacts of relay 603 and through the winding of magnet 611 to battery; and opening at its upper normal contacts the previously tra-ced circuit of relay ST. Relay ST thereupon releases in turn releasing relay 813 whereby the locking circuit of relay 303 is opened at the off-normal contacts'of relay A013. Relay 003 releases in turn releasing magnet B11 to advance the brushes 652 and 054 of switch 650 to the No. 3 terminals of their arcs. When the brush 054 engages with the No. 3 terminal Recording the ycalling office code It will be assumed thatthe oflice in which the calling line is located is designated as ILO-9095 and thatin' response to the identification of the ca'llingofiice al relay SI1 is operated to register the oili'ce designation. The sender `now proceeds to record the' three office-code digits of the direc# toryvv number -of the callingv line upon tape 3| 3. Forthis4 purpose contacts of the register relay 6H* are' cross-connected. to the' terminalsv disclosed in the'central portion of Fig. whose digits values correspond tothe code letters of 'thecalling ofce designation, or connected to the'Nos. 4,' Band G'terminals of the central portion of Fig. 6.

When brush 554 engages the No. 4 terminal of its'V arca circuit is established from ground applied thereover, over conductor BIS, the'lower contacts of register relay' 6I1, terminal 629 strapped to the No. 4 terminal of Fig. 6 and conductorv 626) to battery through the winding of relay 4'of Fig. 6I In the manner previously described' for the start (ST) relay of Fig, 6, the freol'u'enciesl ofl500and 900 cycles are combined by transformer (4)- of Fig. 8 and transmitted to the tape 3I3-over the lower front contacts of relay 4 ofFig; 6,l and switch 650 of the sender is controlled' to advance its 'brushes' 652' andl 554- tothe No. terminals of r4their arcs.

' With brush 654 engaged with the No; 5. terminal' of its' arc, a circuit is' established` from ground thereover, over conductor'GIS to battery and' ground through thewinding'of relay EIB whereupon, as Apreviously'described, switch 65 is controlled to advance its brushes 652and 654 tor the No".r I5V terminals of their arcs; With. brush ''lionthe-No. 6 terminalofits arc a circuit is completed from ground on brush654, over the No'. 6l terminal of' its arc, over conductor'622, upperfin'ner contacts' of relay SI1, terminal 623 connected to' the'No. 5 terminal! and conductor 62'4 to'V battery and ground through. the winding" of relay 5 of the'multifrequency recording relays of Fig-6. When` relay 5 operates.' its lower front contacts complete a circuit whereby, a's previously'des'cribedfor. a similar circuit, themultifrequency'signal from transformer.' (5) of Fig. 8 can be recorded. in. tape' 3 I3.

Inla similar manner' the third oiiice'code digit 6 willf be recorded' on' tape3I3 when brush 654 is 'on' its No. 8` terminal.

Recording'the calling Zine number It will be assumed that the calling-line numerical number is 9095 and that consequently when brush' 654`v engagesV with the No.. lterminal of itslarc, a-circuit is established from ground thereover, over conductor 621, the upper contactsv of relay 628 and the inner lower contacts of relay 625 of the thousands digit register, conductor 626 strapped to the No. 9 terminal of Fig. 6 to battery and ground through the relay 9 of Fig. 6 to thereby transmit the multifrequency signal representing the digit 9 to the tape 3I3. In a similar mannery the switch 650 iscontrolledto. print the hundreds digit, the tens digit and the units digit as'the brush 654 engages the Nos; I2, I4 and I6 position terminals of its arc and applies ground successively tothe-hundreds, tens and units digit registerssimilar to 'the-thousands digitregister so labeled -in Fig. 6. Following' the recording ofithe units digit of 'the calling line numberthe brushes of switch'i ofthe sender areadvancedinto engagement with the subsequent terminals'of their arcsvand'in amannersimilar, to thatdescribedwill'recordon tape 3I3 any desiredim formation'registered in the sender.

When' brush 653 engages the terminal'of its arc following the last'one upon which information appeared for recording in the recorder 360,

ar circuit-is established from ground thereover, over` conductor 629, over contacts ofrelays 10! and 1135/ ofthe sender-trunk connector, conductor 4213| and through the lower windingof relayv 2 4U to battery. Relay 2&0 thereupon operates and locksfrom batteryv through resistance 242, through its upper winding-and'upper No. I contacts, conductor'243, contacts of sender relays not shown, and' over conductor 251, the upper No. 4 back contact of relay 268 to ground'at the upperNo. 5 front contact of-relay'256. Relay 240 `upon operating opens at its upper No. 2 back contact the previously traced circuit forrelay 10B ofthe sendertrunk connector circuit whereupon relay 18S releases and in releasing eiects the release of relay lIIlV at the time thatv the brush 653 or 65'4is ony the next .terminal of its arc. Relay 6 I ll in releasing removes ground from oinormal conductorl 6M? and removes ground from the circuit established 'by they operation of relay 629. Removal of ground'from ofi-normal conductor 604 opens the lockingcircuit of relay 6D2. Relay E02 upon releasing establishes acircuit from ground over its lower No. ilA 'back contact, over the strapped-terminals 'of the arcs of switch 650 associated with brushes-65| and 652, over the interrupter contactsand through the winding of stepping magnet'l I whereby the magnet is intermittently I operated' to advance the brushes of switch 65@ to their-normal positions. Relay 602 also releases relay 6&5 which in turn releases the lock-out relay 1M ofthe sender-trunk connector circuit which in turn releases the multicontact relay 10| thereby restoring the sender trunk connector circuit to its normal condition-and'thereby opening thecircuit of relay 30.1 to stop motor 3| I.

The release of 'relay SII) is accompanied by releasevof all operated relays of the sender including relay 690 by causing the opening of the conductor Sill inthe locking circuit of relay 600. The release-'of relay EID causes the initiation of the release oftheV trunk finder 59D. When the trunk finder is restored to normal the circuit of relay 291 of the trunk is opened and relay-201 releases. The release of the trunk finder 500 and of relay 231 permits relay 2|!) to release to normal from itsv previously operated condition in which its lower contacts were closed. The release of all operated relays in the sender opens the holding circuit for relay 24U at its upper winding thereby permitting relay 240 to release.

At the end of the conversa-tion, when the calling subscriber restores his receiver to the switchhook, relay 2 I 1 of the trunk circuit releases in turn releasing relay 205. The release of relay 266 will remove holding ground from relay 2I6 and from thersleeve conductor of the trunk applied over its lower front contact, thereby releasing relay 2I6 and initiating the release of the selector switches which were operated to connect the calling line-with the trunk and release of the sleeve relay 293 and relay 204. Relay 206, upon releasing, will also establish a circuit for relay 208 which may be traced from battery through its'upper winding, over the lower No.5

contacts of relay 255, conductor 244, the upper No.2 back contact of relay 240, conductor 245 to ground over 'the upper back contact of relay 206. Relay 208 upon operating extends its operating ground overxits upper No. 2 front contacts, over conductor 246 through the windingof relay 21| to battery whereupon relay 21| operates to con- 'nect ground to sleeve conductor 202 of the ticketing-trunk to Vmarl: the trunk Abusy to all selector switches. vRelay 208 will remain operated until the completion of the recording ofthe elapsed conversationtime on the record tape. When the called subscriber restores his receiver to the .switchhook relays 223 and 228 will release.

'Recording the elapsed time With relay 208 operated in the manner de- "scribed, it opens the locking circuit for relay 228 Iat its upper No. 3 back contact allowing relay 228 to release; closes a circuit from ground over its lower No. 2 front contact, conductor 241, the upper back contact of pulse-help relay 248, brush 25| of register 250, over the No. I terminal of the ,y

arc'of register 250, over conductor 249 and to ground through the normal contacts and winding of relay 305 and battery and in parallel through the winding of relay 3|8 and battery.

Relay 308 operates and locks over its inner lower alternate contacts, and conductor 3|5 to ground over' the lower No.V I front contacts ol A circuit is completed for relay 301. voverthe lower contacts of relay 30B to ground relay 208.

whereupon motor 3|| is energized from source v 3I0 over the `front contacts of relay 301. Motor 'K 3l will resume its Vmovement of tape 3|3 preparatory to recording thereon the elapsed time. Relay 305, in operating, furthermore transfers the circuit of the magnetizing coils 3M, appearing on its upper armatures, from the conductors V185 and 1I0 to conductors 3|6 and 3|1 and thus thc front contacts of the elapsed time relays (STOP,

1.2, 3. 4. 5. 6,1,8, e, c) of Fig. 3.

Relay 3|8 upon operating establishes a circuit from ground over its inner contacts, conductor v 26 I, lower No. 4 contacts of relay 20B and through the winding of pulse help relay 248 to battery and ground. Relay 248 thereupon operates, locks over` its inner lower contacts and conductor 202 to ground over the outer contacts of relay 3|8.

establishes the circuit of stepping magnet 253 of switch 250 which extends from battery through the winding of magnet 253, the upper contacts of relay 248 and to ground at the upper No. 5 contacts of relay 256, and at its upper back contact establishes the previously traced circuit of relay 3I8 which releases and opens both the energizing and the locking circuits for pulse help relay 248. Thereuponv relay 248 releases opening the circuit of stepping magnet 253 which releases and ad- -vances brush into engagement with the No. 2

terminal of its associated arc.

The operation of relay 208 and the release of `time was such as to leave the brushes of switch L300 on the No. 3 terminals of their arcs and the brushes c; switch e, namely 356, 354 and 352, on the No. 25 terminals of their arcs. This will be the case when the elapsed time has been 30 minutes.

A'14 With relay 208 operated and relay'228 released a circuit is completed for relay 239, which ciricuit may be traced from battery,`through the winding of relay 230, over the lower No. 3 back lcontact of relay 220, lower No. 3 back contact of relay 228, upper No. 4 front contact of relay 208, to ground over the upper No. 5 contacts of relay 256 whereupon relay 239 operates.

Relay 239 in operating further opens the oper- 'ating circuits of stepping magnet 303 at the lower No. 3 back contact of relay 239 and of stepping magnet 305 at the upper No. 2 and No. 4

back contacts of relay 239.

With switch 258 in theposition where its brush 25| is on the No. 2 terminal of the switch, a circuit may be traced for the 4elapsed time recording relay 3 (Fig. 3) and forthe interrupter relay 318 as follows, from ground over the lower No. 2 front contact of relay 208, conductor 241, upper back contactfof relay 248, brush 25| of switch 250, No.

2 terminal of switch 250, upper No. front contact of relay 208, conductor 260, lower off-normal contacts of switch 322, brush 30| of switch 300,

the No. 3 terminal of the associatedV bank,

through the winding of recording relay 3 and in.- terrupter relay 3|8 and battery to ground. Recording relay 3 and relay 3|8 will operate, the former to close over its upper front contacts a circuit for transmitting combined frequencies of 1300 cycles and 1500 cycles from transformer-(3) of Fig. 8. This circuit extends from transformer (3) over conductors 801 and 808, over the upper front contacts of recording relay 3 of Eig'. 3, over conductors 3I9 and 32|),v conductorsV 3|1 and 3|3, upper front contacts of relay 303, upper back contacts oi relay 309, upper and lower middle back contacts of relay 308 to magnetizing coils 3M. The digit 3 is thereby recorded on tape 3I3 indicating that the tens digit of the elapsed time is 3.

Relay 3|8, being slow' to operate, completes the operating and holding circuits for relay 248; The operating circuit may betraced from ground and battery through the winding of relay 248, over the lower No. 4 front contacts of relay 208, over conductor 25|, to ground 'over the operated contacts of relay SIS. The holding circuit may be traced over the lower inner front contacts of relay 248, over conductor 262, to ground over the operated contacts of relay 3|8. Relay 248 operates and in doing so opens the operating circuits of recording relay 3 and relay 3|8 at the upper back contact of relay 248. Recording relay 3 and relay 3|8 release and in doing so remove the i, operating and holding ground from the winding of relay 248 which in turn releases. During the operation and release of vrelay 248 a circuit was closed and opened at the upper front contacts of relay 228 for stepping magnet 253. This circuit may be traced from ground and battery through the winding oi magnet253, over the upper front 'contacts of relay 248, and upper No. 5 front contact of relay 255 to ground. Magnet 253 in operating and releasing stepsthe'brush 25| of switch 250 to its No. 3 terminal. A circuit is now completed for operating recording relay 6 of v:the elapsed time register. This circuit extends'from ground over the lower No. 2 front contact of relay 208, upper back contacts of relay 24B, brush 25| and No. 3 terminal of switch 250, conductor 263, brush 354 of switch 350, No. 25 terminal '-.of its arc, through the winding of recording relay 5 and interruptor relay 3|8 to battery and ground. As before the operationr of the recording relay enables transmission. to and recording on. tape 31I3;of the frequencies'corresponding to theV particular recording relayl which is; operated, '700 cycle-sand 1100 cycles, from transformer (6) in this case. The operation of relay 3|8 againoperates relay 240 which in turn operates magnet 253 as before to step switch 250 to the No. 4 terminal of its arc to thereby open the operating circuits of recording relay 6 and interruptor relay 3I8 as previously explained. Similarly as explained before, acircuit is established over the No. 4 terminalof switch 250 and conductor 264 for the STOP relay of the elapsed time register to, record on tape v3 I3 a STOP signal, composed of frequencies 1100 cycles and 1'700 cycles from transformer VSTOP of Fig'. 8. Relay 3|,8 again effects thestepping; of switch 250 to its No. terminal as previously described.

' Contact of brush 25| with the No. 5 terminal orswitch 250 completes anobvious circuit for relay 2|| which operates thereover. Operation of relayv 2|I removes the ground from its normal contacts thereby releasing relay 250. The release of relay v250 opens at its lower No. 5 front con- Vtact the operating circuit of relay 203 which thereupon releases. With relay 208 released the locking circuit of relay 306 is opened at the lower No. I front contacts of relay 208 whereupon relay- 306 releases. With relay 30|released` the operating circuit of motor control relay 301 is opened at the lower contacter' relay 306 whereupon relay 301 releases stopping motor 3| I from moving tape 3 I3. The release of relay 208 establishes a circuit for release magnet 254 which may be traced from ground, over the lower No. 3 back contact of relay 208, upper contacts of off-normal switch 255 associated with switch 250 and closed when switch 250 was stepped from normal, over conductor 255, upper outer back contact of relay 2|0, conductor 266, to battery and ground through the winding of' release magnet 254. Operation of magnet 254 releases switch 250 to normal whereupon the operatingY circuit of magnet 254 is opened at ollnormal switch255 to release magnet 254. The release of relay 208 also opened the operating circuit of relay 235 at the upper No. 4 front contact of relay 200 whereupon relay 230 releases. The restoring circuit for the units. timing register 350 is now established from battery through the windingl and interrupter contacts of the stepping .magnet 305 thereof, over the upper No. 4 back contact of relay 239, conductor 261, the lower No.

back contact of relay 256, conductor 258, over the strapped terminals associated with brush 352 and thence over brush 352 to ground to advance all the brushes to the No. I terminals of their arcs, in which positions no circuit is effective tofurther operate magnet 305.

With brush 35| now in engagement with the normal terminal of its arc, a circuit is established from ground thereover, over the lower No. I back contact of relay 230, over the upper contacts of off-normal switch 322, since register 300 has been advanced from normal, over conductor 32|, the lower No. 3 back contact of relay 250 and conduct'or 209 to battery through the winding of releaseA magnet 304. Magnet 304 upon operating causes the restoration of brushes 30| and 302 of register 300 to their normal positions, whereupon the off-normal switch 322 is restored to release magnet 304. All of the operated apparatus of vthe trunkvhas now been restored to normal. The tape: 3I3 now has recorded thereon all of the informationrequired for billing the call.

Transmission of recordad inform-attuato account.- mg olice 4rior tio the release of relay 2I| when switch 250- was restored to normal, a circuit was establishedy for the operation of relay 400 over start conductor 210. This circuit may be traced from ground, over the front contact of relay 2 I I, over start conductor 270 to battery and ground through the winding of relay 400. Relay 400 in operating locks over its right inner front contacts, over the right back contacts of relay 40|; over conductor 402 to ground over the lower outer back contact of relay 308. A circuit is completed for relayy 403 from ground, over the right outer back contacts of relay 404 and left inner front contacts ofV relay 400'to battery and ground through the winding of relay 403. Relay 40.3 in operating sets into motionv the necessary stepping mechanism for connecting the recording unit 360 with anidle central accountingy oce trunk circuit shownV diagrammatically in Fig. 4 which trunk circuit has connected thereto an idle register 401 to be used for decoding the frequencies found on tape 3I3 and operating the necessary equipment in accordance with the decoded information to effect operation of a card punching machine or teletypewriter 408.

Such a register as is disclosed in Patent No. 2,237,742 granted April 8, 1941, to A. A. Lundstrom or in Patent No. 2,332,912 granted October 26, 1943, to G. Hecht et al. or in my copending application Serial No. 772,092 iiled concurrently herewith, may be used as the apparatus designated in Fig. 4 as 40'! along with amplifier 4I8. The selection of an idle link circuit such as is shown diagramatically in Fig. 4 is a well-known procedure and involves well-known apparatus. For a more complete disclosure thereof reference may be had .to Patent No. 1,780,906. granted November 11, 1930, to W. W. Carpenter and R. E. Hersey.

When the idle trunk circuit has been found the brushes 40S, 4|0, 4|| and 4|2 of the trunk nder H3 will be connected over a link to corresponding brushes of the trunk nder 450. 'A circuit is then completed for relay 4I4 from ground over the left front contacts of relay 406, conductor 4|5, brush 4| I, conductor 4|6, left outer back contact of relay 404, right outer front contact of relay 400, to battery and ground 'through the winding of relay 4|4. Relay 4|4 in .operating completes the operating circuit of relay 404 from ground, over the leftV outer front `contacts of relay 400, left front contacts of relay 4M, to battery and ground through the winding of relay 404. Relay 404 in operating locks to ground over the left outer front contact of relay 400, opens the operating circuit of relay 403 at the right outer back contact of relay 404 thus releasing relay 403, and completes a circuit for relay 300. The circuit of relay'300 maybe traced from ground, over the left middle front contacts of relay 404, over conductor 4|"I to batteryy and ground through the winding of relay 309, which thereupon operates. Relay 309 in operating transfers the magnetizing coil circuit over its upper front contacts to conductors 323 and v324 which extend over brushes 4|0 and 409, through amplier H0 to the register 401. Relay 309 in operating completes a circuit for motor control relay 30? over the lower outer front contact of relay 309 whereupon motor SII is energized to move tape 3I3. As soon as tape 3I3 begins to move a locking ground is applied to the winding of relay 309 over its lower inner front contacts from olf-normal switch 325 associated with gear train 312. Thus relays 301 and 309 will remain operated until tape 3|3 has made at least one complete revolution whereupon this locking circuit will be opened at switch 325.

The magnetizing coils 3|4 will act as pick-up coils and will transmit the information recorded in tape 313 to the register 401 of the accounting office. If, for any reason, register detects a mistake or other maloperation it will effect the operation of relay 4|9 to request a retransmission of the information and release the link nnder switch 4|3. The operation of relay 4|!! applies ground over its contacts, over conductor 420, brush 4|2, conductor 42| to the winding of relay which thereupon operates. The operation of relay 40| opens at its right contacts the locking circuit of relay 400. The release of relay 400, releases relays 404 and 4|4. The release of relay 404 opens' the operating circuit of relay 309 which nevertheless, in conjunction with relay 301, will remain operated, as previously eX- plained, until tape 3|3 has made a complete revolution, whereupon relays 301 and 309 both release to normal stopping the energization of motor 3| I. f

The operation of relay 40| also applies ground over its left outer front contacts to the cold cathode tube timing circuit 422 which, after a suitable period of time necessary for the line finder 4|3 to restore to normal and for tape 3|3 to make a revolution, will enable the operation of relay 423. In the meantime relay 40| was locked operated over its left inner front contacts and to ground over the back contacts of relay 423. When relay 423 operates the locking circuit for relay 40| is opened and relay 40| releases reconditioning the previously mentioned locking circuit for relay 400 over the right back contacts of relay 401 and opening the circuit of the timing tube 422 which in turn releases relay 423. During the interval when relay 423 was operated the operating circuit of relay 400 was reestablished over the front contacts of relay 423 whereupon an idle link is found and the preceding procedure is repeated. A

When the register 401 detects the STOP signal on tape 3|3 relays 405 and 400 are released and the link finder switch 4|3 is restored to normal. When relay 400 released ground was removed from conductors 415 and 4|6 to open the locking circuit of relay 4 I4 which thereupon releases. Relay 4|4 upon releasing establishes a circuit for wipe out relay 308 which circuit extends Vfrom ground, over the left outer front contact of relay 4.00, left outer back contact of relay 4|4, right inner front contact of relay 404, over conductor 424, to battery and ground through the winding of relay 308'. Relay 308 in operating completes a circuit over its lower outer front contacts for relay 301 to Ystart motor 3| l, and relay 308 is locked up over its lower middle front contacts and ofi-normal switch 325 to ground until motor 3|| has revolved tape 313 at least one complete turn. Relay 308 in operating applies direct current from battery 326 over its upper and lower middle front contacts to the coils 3|4 mipe out the signals previously recorded on tape 3|3.

When relay 308 operated the locking circuit of relay 400 was opened at the lower outer back contact of relay 308. Release of relay 400 eiects release of relay 404 as previously described and all relays will be released except relays 301 and 308. When tape 3|3 has made a complete revolution, during which time all signals thereon have fire been erased or wiped out by battery 320, the olinormai switch 325 will open to release relays 301 and 303 whereupon all relays and equipment have been returned to normal.

The invention is not intended to be limited to the particular embodiment thereof herein disclosed; consequently, claims are appended which alone denne the scope of this invention.

What is claimed is:

l. In an automatic telephone system, a calling line, outgoing trunks, a magnetic recorder in- -cluded in each of said trunks, means under the control of said calling line for establishing a connection from said line over one of said trunks, means under the control of said connection for registering items of information appertainingto said connection, means under the control of said registering means for transmitting to the recorder said one trunk signals in accordance with the setting of said registering means, registering circuits common to said trunks, means under the control of said one trunk for connecting the recorder of said one trunk to an idle one of said circuits, and means controlled by said one circuit for reproducing said signals recorded in the recorder of said one trunk and for transmitting said signals to said one registering circuit.

2. In an automatic telephone system, a calling line, outgoing trunks, a magnetic recorder included in each of said trunks, means controlled by said calling line for establishing a connection from said line over one of said trunks, means controlled by said connection for registering items of information appertaining to said connection, means under the control of said registering means for transmitting to the recorder of said one trunk signals in accordance with setting of said registering means, registering circuits common to said trunks, means under the control of said one trunk for connecting the recorder of said one trunk to an idle one of said circuits, means controlled by said one circuit for reproducing said signals recorded in the recorder of said one trunk and for transmitting said signals to said one registering circuit, and means under the control of said one circuit for wiping out the record in the recorder of said one trunk following the completion of transmission of said record to said one registering circuit.

3. In an automatic telephone system, a calling line, an outgoing trunk, a magnetic recorder included in said trunk, means controlled by said calling line for establishing a connection from said line over said trunk, means under the control of said connection for registering items of information appertaining to said connection, means under the control of said registering means for transmitting to said recorder alternating-current signals of different combinations of frequencies in accordance with the setting of said registering means, registering circuits common to said trunk, means under the control of said trunk for connecting said recorder with an idle one of said circuits, `and means under the control of said one circuit for reproducing said alternating-current signals recorded in said recorder and for transmitting said signals to said one registering circuit.

4. In an automatic telephone system, a calling line, an outgoing trunk, a magnetic recorder included in said trunk, means controlled by said calling line for establishing a connection from said line over said trunk, means controlled by said connection for registering items of informa'- tion appertaining to said connection, means controlled by said registering means for transmit- 19 ting to said recorder alternating-current signals of different combinations oi' frequencies in accordance with the setting of said registering means, registering circuits common `to said trunks, means under the control of said trunk for connecting said recorder with an idle one of said circuits, means under the control of said one circuit for reproducing said alternatingcurrent signals recorded in said recorder and for transmitting said signals to said one registering circuit, and means under the control of said one circuit for wiping out the record in said recorder following the completion of transmission of said record to said one registering circuit.

5, In an automatic telephone system, a calling line, outgoing trunks, each trunk having a magnetic recorder included therein, means under the control or said calling line for establishing a connection from said line over an idle one cf said trunks, a sender connectable under the control of said connection With said one trunk and having registers for registering items of information appel-taining to said connection, means controlled by said sender for transmitting to the recorder of said one trunk alternating-current signals of dierent combinations of frequencies in accordance with the setting or said registers of said sender, registering circuits common to said trunks, means under the control of said one trunk for connecting the recorder' of said one trunk with an idle one of said circuits, and means under the control of said one circuit for reproducing said alternating-current signals recorded in the recorder of said one trunk and for transmitting said signals to said one registering circuit.

`6. In an automatic telephone system, a calling line, outgoing trunks, each trunk having a magnetic recorder included therein, means under the control of said calling line for establishing a connection from said line over an idle one of said trunks, a sender connectable under the control of said connection with said one trunk and having registers for registering the digits of a Wanted line designation, an identier connectable under the control of said connection with said sender and having registers for registering the digits of the calling line designation, means under the control of said sender and said identifier for transmitting to the recorder of said one trunk alternating-current signais of different combinations of frequencies in accordance with the setting of said registers of said sender and said identifier, registering circuits common to said trunks,.means under the control of said one trunk for connecting the recorder of said one trunk with an idle one of said circuits, and means under the control of said one circuit for reproducing said alternating-current signals recorded in the recorder of said one trunk and for transmitting said signals to said one registering circuit.

7. In an automatic telephone system, a calling line, outgoing trunks, each trunk having a magnetic recorder included therein, means under the control of said calling line for establishing a connection from said line over an idle one of said trunks, a sender connectable under the control of said connection with said one trunk and having registers for registering the digits ofa wanted line designation, an identier connectable under the control of said connection with said sender and having registers for registering the digits `ofthecalling line designation,means under the control of said identier for registering said digits of said calling line designation in registers of said sender, means under the control of said ,sender for transmitting to the recorder of said one trunk alternating-current signals of different combinations of frequencies in accordance with the setting of said registers of said sender, registering circuits common to said trunks, means under the control of said one trunk for connecting the recorder of said one trunk with an idle one of said circuits, and means under the control of said one circuit for reproducing said alternating-current signals recorded in the recorder of said one trunk and for transmitting said signals to said one registering circuit.

8. In an automatic telephone system, a calling line, outgoing trunks for extending connections to wanted lines each trunk having a magnetic recorder included therein, means under the control of said calling line for establishing a connection from said calling line to an idle one of said trunks, a sender connectable under the control of said connection with said one trunk and having registers for registering the digits of a wanted line designation and the digits of the calling line designation, said sender adapt-cd to control the establishment of a connection from said one trunk to a- Wanted line, a register included in said one trunk for registering the elapsed time of a conversation between a calling and a called subscriber, means under the control of said sender for transmitting to the recorder of said one trunk alternating-current signals o1 different combinations of frequencies in accordance with the setting of said registers of said sender, means under the control of said one trunk for transmitting to the recorder of said one trunk alternatingcurrent signals of different combinations of frequencies in accordance with the setting of said elapsed time register, registering circuits common to said trunks, -means under the control of said one trunkfor `connecting the recorder of said one trunk with an idle one of said circuits, and means under the control of said one circuit for reproducing said alternating-current signals recorded in the recorder of said one trunk and for transmitting said signals to said one registering circuit.

9. In an automatic telephone system, a calling line,V outgoing trunks for extending connections to wanted lines, each trunk having a magnetic recorder included` therein,rmeans under the control. of, said calling line. for establishing a connection from said calling line to an idle one` of said trunks, a sender connectable under the control of said connection with said one trunk and having registers for registering the digits of a Wanted line designation, .an identifier connectable under the control ofv said connection with said sender -and having registers for registering thedigits of the =calling `line designation, said sender adapted to control the-establishment of a connection from said one trunk to a ywanted line, a register included in said one trunk for registering the elapsed time of a conversation between a calling and a called subscriber, means under the control of said sender and said identier for transmitting to the recorder of said one trunk alternating-current signals of different combinations -of frequencies in accordance with the setting of said registers of said sender and said identiiier, means under the control of said one trunk for transmitting to the recorder of said one trunk alternating-current signals of dilerent combinations of frequencies in accordance with the setting of-said elapsed time register, registering circuits common to said trunks, means under the control of said one trunk for connecting the recorder vof said one trunk to an idle one of said circuitsfand means under the control of said Vone circuit for reproducing the alternating-current signals recorded in the recorder of said one trunk and for transmitting said signals to said v vone registering circuit.

10. In an automatic telephone system, 'acalling line, outgoing trunks for extending connections to wanted lines, each trunk having amagnetic recorder included therein, means under-the control of said calling line for establisning'a "connection from said calling line to an idle-'tine of said trunks. a sender connectable underV vthe control of said connection with said onetrunk and having registers for registering thejxdigits of said wanted line designation, an identifier connectable under the control of said connection with said sender and having registers forregistering the digits of the calling line designation, means under the control of said identifier for registering said digits of said calling line dsignation in registers of said sender, said sender 'adapted to control the establishment of a connection from said one trunk to said Wanted line, a register included in said one trunk for registering the elapsed time of a conversation between a calling and a called subscriber, means under the `control of said sender for transmitting to the recorder a1- ternating-cun'ent signals of different combinations of frequencies in accordancevwith the setting of said registers of said sender',"means under the control of said one trunk for transmitting to the recorder of said one trunk alternating-current signals of, different combinations of frequencies in accordance with the'setting of said elapsed time register, registeringcircuits common to said trunks, means under, the control of said one trunk for connecting the 'recorder of said one trunk to an idle one of saidi'circuits, and means under the control of saidfone circuit for reproducing said alternating-current signals recordedin the recorder of said-ione trunk and for transmitting said signals to `said one registering circuit. l f

' JOHN B;`RETALLACK.

REFERENCES CITEDj The following references are of record in the iile of this patent:

UNITED STATES PATENTS 

